Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare this as read-only, idempotent, and non-destructive, and the description adds substantial behavioral context beyond that: it discloses that autofillScript is not returned, that valuePreview fields are masked, that externalIsCanonical changes where the real submission happens, that requiresPhoneVerification has two branches, and that unconfigured signups will cause submit_signup to reject with signup_not_open. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is long but not bloated; it is organized into clear sections ('何时用', '组合链', '口径/坑') and each bullet addresses a real decision an agent would face. It is front-loaded with the primary use case and one-call value proposition. A slight deduction because the density is heavy, but every item earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with a single parameter and no output schema, the description is remarkably complete. It enumerates the return content, identifies consumed fields like viewer.missingRequired and valuePreview, and explains seven edge-case behaviors that materially affect whether the agent should continue to submit_signup, fetch the agreement, or direct the user to the App. Nothing essential for correct invocation is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already documents the lone slug parameter thoroughly with its source ('取自 list_signup_feed 的 items[].slug'), so coverage is 100%. The description references slug in the submit chain but adds no new semantic constraints or format details beyond what the schema provides, leaving the baseline of 3 appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states a specific verb and resource: view a single event's signup details plus the caller's own signup status. It distinguishes itself from siblings by naming exactly what it returns (public details, my status, per-question values, missing required fields) and by routing to alternatives like get_signup_gaps and list_my_signups.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The opening line gives an explicit when-to-use condition: when the user is interested in a specific event or about to sign up. The '组合链' section provides concrete decision rules with named alternatives — get_signup_gaps for multi-event gaps and list_my_signups after submission — so an agent knows exactly when to choose this tool over siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.